Monobath containing cysteine-nitrogenous base combination



United States Patent 3,343,958 MONOBATH CONTAINING CYSTEINE-NITROG- ENOUS BASE COMBKNATION Meroe M. Morse, Boston, Mass, assignor to Polaroid Corporation, Cambridge, Mass., a corporation of Delaware No Drawing. Filed Apr. 9, 1965, Ser. No. 447,069 19 Claims. (Cl. 9629) This invention relates to photography and, more particularly, to novel photographic processing compositions and processes employing the same.

One-step processes for developing an exposed photosensitive element comprising a light-sensitive silver halide emulsion to form a fixed negative image thereon are well known in the art. Generally speaking, the exposed photosensitive element is contacted with'a developing composition containing a silver halide developing agent and a silver halide solvent-fixer for a time sufiicient to develop and fix the negative image.

In one-step processes of the foregoing description, there is a tendency for the soluble silver complex contained in the solvent-fixer to migrate back to the negative and precipitate as image silver, thereby increasing the D or causing unwanted formation of image silver in the highlight areas of the negative image. In addition, the solvent-fixer employed may cause undesirable color changes if left on the surface of the negative for any appreciable length of time.

For the foregoing and for other reasons, it has heretofore been the practice to subject the image to some aftertreatment such as washing in order to remove the spent processing composition from the image.

The present invention is directed to novel developing compositions containing a novel combination of ingredients which function together to provide the silver halide solvent for fixing the negative image. In other words, the present invention is directed to photographic processing compositions containing a novel silver halide solvent system. The compositions of this invention When employed in one-step photographic processes of the foregoing de scription makes it possible to eliminate the aftertreatment I heretofore employed to protect the quality of the image.

A primary object of this invention, therefore, is to provide novel photographic processing compositions containing a novel silver halide solvent system, and photographic processes employing the same.

Another object is to provide a novel combination of ingredients for forming transparent silver complexes and processing compositions containing the same.

Still another object is to provide novel combinations of ingredients for forming transparent silver complexes which will not precipitate as image silver, and processing compositions containing the same.

Yet another object is to provide a novel one-step photographic process for preparing negative images which require no aftertreatment to retain their quality for extended periods of time.

The invention accordingly comprises the process involving the several steps and the relation and order of one or more of such steps with respect to each of the others, and the product possessing the features, properties and the relation of elements which are exemplified in the following detailed disclosure, and the scope of the application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description.

It has now been discovered that the combination of 3,343,958 Patented Sept. 26, 1967 cysteine (a-amino-[3-mercapto-propionic acid) and a nitrogenous base, preferably a volatile nitrogenous base, provides the silver halide solvent for forming from the unexposed silver halide a highly stable, transparent, silver complex. This complex and the aforementioned combination of ingredients have been found to have no adverse effect upon the negative image and need not be removed from the finished negative after development.

As examples of nitrogenous bases useful in the practice of this invention, mention may be made of the following compounds: ammonia, sec. amylamine, ethylamine, n-butylamine, allylamine, diethylamine, dipropylamine, trimethylamine, triethanol amine, diethylene triamine, triethylene tetramine, N-hydroxyethyl propylene diamine, trimethylene diamine, ethylene diamine, aminoethyl ethanol amine, hydroxyethyl diethylene triamine, tetraethylene pentamine, guanidine hydrochloride, piperidine, pyrrolidine, 2,5-dimethyl piperazine, polyethylene irnine, symmetrical dimethyl hydrazine and unsymmetrical dimethyl hydrazine.

Nitrogenous bases such as those illustrated above have heretofore been known in the art as silver complexing agents. However, these compounds are not effective complexing agents alone and have heretofore been employed in combination with other complexing agents such as cyclic imides in processing compositions for preparing silver transfer images. The use of nitrogenous bases in diffusion transfer photography is disclosed in U.S. Patent Nos. 2,857,274, 2,857,275 and 2,857,276.

Cysteine has also been previously employed in processing compositions for preparing silver transfer images. U.S. Patent No. 2,984,565 discloses the use of cysteine to render the resulting silver transfer image substantially more neutral in tone, e.g., blue-black, as compared with the image which would be obtained in its absence.

However, it has never been suggested, prior to the present invention, that the combination of cysteine and a nitrogenous base could produce a transparent silver complex, much less a silver complex of such stability that neither these ingredients nor the silver complex resulting therefrom need be removed by washing the developed negative, as in prior processes.

The novel combination of fixing ingredients of this invention may be employed in lieu of the fixers heretofore employed in aqueous processing compositions for developing and fixing a negative image. Such compositions typically contain an alkaline material such as sodium hydroxide, sodium carbonate, etc., and at least one silver halide developing agent such as the benzene and naphthalene compounds having hydroxy or amino substituents ortho or para to one another, e.g., hydroquinone, 1,2- dihydroxybenzene, toluhydroquinone, para-aminophenol, etc.

However, in the preferred embodiment, the present invention is employed in combination with the invention described and claimed in my copending application Ser. No. 438,044 filed Mar. 8, 1965.

As is disclosed and claimed in this copending application, the necessity of some after-treatment such as washing to prevent the harmful effects resulting from the presence of exhausted and/or unexhausted developing agent on the negative is greatly reduced, if not obviated, by employing the combination of a high concentration of a low-energy silver halide developing agent and an extremely low concentration of a high-energy silver halide developing agent. The synergistic effect so obtained greatly expands the usefulness of such high-energy silver halide developing agents. Many high-energy silver halide developing agents are known. The invention is primarily concerned with high-energy developing agents which contain at least one amino group substituted on the ring of a.

phenol, particularly 4-amino-phenols further substituted by lower alkyl, lower alkoxy and/ or amino groups in positions ortho to the hydroxyl group. Particularly useful examples of such high-energy silver halide developing agents include 2,4-diamino-ortho-cresol, 4-amino-2,6-dimethylphenol and 2,6-dimethoxy-4-amino-phenol. Other examples of suitable high-energy silver halide developing agents may be found in US. Patent No. 3,091,530 issued May 28, 1963, to Milton Green, Meroe M. Morse, and Myron S. Simon and U.S. Patent No. 3,108,001 issued October 26, 1963, to Milton Green. Particularly useful low-energy silver halide developing agents are those which have substantially colorless oxidation products and/or are volatilized from the image, particularly the ascorbic acids, such as ascorbic acid, isoascorbic acid, etc., and hydroxylamines, such as N,N-diethyl-hydroxylamine, N,N-diethoxyethyl hydroxylamine and N,N dimethoxyethyl-hydroxylamine. Suitable hydroxylamine silver halide developing agents include those disclosed in US. Patent No. 2,857,276 issued October 21, 1958, to Edwin H. Land et al., and the copending application of Milton Green, Adna A. Sayigh and Henry Ulrich, Serial No. 290,618 filed June 26, 1963.

As stated above, the high-energy silver halide developing agent is used in extremely low concentrations, i.e., a concentration ineifective, if used as the sole developing agent, to develop appreciable negative density, e.g., less than about 0.3, within the predetermined, usually very short, processing period. Although the low-energy silver halide developing agent is used in substantial concentrations, it too is ineffective to develop appreciable negative density within the predetermined processing period if used in that concentration as the sole developing agent.

Since this combination of developing agents has been found to act synergistically to provide a mixture of ingredients capable of developing an exposed silver halide emulsion to obtain a silver image of excellent density and detail without leaving any reagents capable of impairing the quality of the image, it will therefore be appreciated that when the novel combination of ingredients of this invention is employed in a processing composition containing the novel combination of developing agents described and claimed in the aforementioned copending application, it is possible to obtain in a single step a negative image which requires no further treatment to retain the quality of the print.

The following examples show by way of illustration the preferred embodiment of this invention:

Example 1 A photosensitive element having a silver iodobromide emulsion on film base was exposed and then developed by spreading between the thus-exposed emulsion and a superposed surface-hydrolyzed cellulose acetate spreader sheet a processing composition comprising:

Water cc. 902.0 Hydroxyethyl cellulose grams 41.5 Sodium sulfite do 33.0 Potassium thiosulfate do 14.0 Ascorbic acid do 60.0 2,4-diamino-orthocresol do 2.0 Cysteine do.. 2.2 Diethylamine cc. 50.0 Sodium hydroxide grams 25.0

After an imbibition period of 40 seconds, the spreader sheet was removed to reveal a fully developed and fixed negative having a D of 1.5 and a D of 0.2. There was no image in the solidified layer of processing composition adhered to the separated cellulose acetate spreader sheet. The unwashed negative was completely dry in about three to five minutes.

The negative image prepared in Example 1 was subjected to accelerated tests for stability to light, heat and humidity (ultraviolet lamp for 72 hours; relative humidity at F. for 40 hours; 80% relative humidity at F. for 16 hours in the presence of powdered sulfur), and was found to be exceptionally stable although perhaps not of archival stability. A fully developed and fixed negative prepared as described in Example 1 has been found to be stable, e.g., no density fading and density increase in highlights, when stored at room temperature and humidity for over two years.

Example 2 Example 1 was repeated, except that the spreader sheet was not removed from the developed negative, so that the resulting image was a sandwich-type negative which is viewable through the transparent spreader sheet. This sandwich-type negative could be printed immediately.

This negative was found to be of substantially the same stability as the negative prepared in Example 1.

Example 3 Example 1 was repeated, eliminating the ascorbic acid from the developing composition. An extremely faint (D 0.15 above base density) image was obtained.

Example 4 Example 1 was repeated, eliminating the 2,4-diaminoorthocresol from the developing composition. The resulting image was even fainter or had even lower density (D 0.05 above base density) than the negative prepared in Example 3.

From Examples 3 and 4, it will be observed that the density obtained from the combination of ascorbic acid and 2,4-diamino-orthocresol is appreciably greater than the sum total of the densities obtained from the same concentrations of the individual components. In other words, there is a synergistic reaction between the two developing agents, neither of which alone was capable in the concentrations used in Example 1 of providing a visible image of usable density, to provide, in combination, an image of excellent density and contrast.

Example 5 The procedure of Example 1 was repeated a plurality of times, each time substituting for diethylamine one of the following nitrogenous bases: ammonia; ethylamine; nbutylamine; allylamine; dipropylamine; trimethylamine; diethylene triarnine; triethylene tetramine; ethylene di amine; aminoethyl ethanol amine; tetraethylene; pentamine; guanidine hydrochloride; piperidine; pyrrolidine; 2,5-dimethyl piperazine; polyethylene imine; symmetrical dimethyl hydrazine; and unsymmetrical dimethyl hydrazine. In each instance a negative image was obtained.

In the foregoing illustrative examples it will be noted that the processing composition contained potassium thicsulfate, a known silver halide solvent-fixer, in relatively small amounts, e.g., in an amount insufficient in and by itself to provide the desired fixed negative image. Although not necessary in the practice of this invention, the presence of a small amount of sodium or potassium thioulfate has been found to lower appreciably the imbibition time necessary to obtain a fixed negative image of the desired density and contrast, i.e., there is a synergistic or accelerating effect upon the fixing action of the cysteinenitrogenous base combination.

The following illustrative examples show by way of illustration and not by way of limitation the preparation of a comparable negative image in the absence of potassium thiosulfate by employing longer imbibition times.

Example 6 A photosensitive element similar to that described in Example 1 was exposed and then developed by spreading between the thusexposed element and a superposed surface-hydrolyzed cellulose spreader sheet a processing composition comprising:

Water cc 902.0 Hydroxyethyl cellulose grams 41.5 Sodium sulfite do 33.0 Ascorbic acid do 60.0 2,4-diamino-orthocresol do 2.0 Cysteine do 22.0 Diethylamine cc 50.0 Sodium hydroxide grams 25.0

After an imbibition period of three minutes, the spreader sheet was removed to reveal a fully developed and fixed negative comparable in density and stability to that obtained in Example 1.

Example 7 A Kodabromide F-3 emulsion (trade name of Eastman Kodak Co., Rochester, N.Y., for a fast enlarging paper containing predominantly silver bromide as the light-sensitive material) was exposed to a negative and then developed by spreading between the thus-exposed emulsion and a superposed surface-hydrolyzed cellulose acetate spreader sheet a processing composition comprismg:

Water 902.0

Hydroxyethyl cellulose grams 41.5 Ascorbid acid do 60.0

Cysteine do 31.9 Diethylamine cc 50.0 Sodium hydroxide grams 25.0

Example 8 Example 1 was repeated substituting for the spreader sheet an image-receiving element comprising a silverreceptive stratum containing nuclei for precipitation of silver such as commonly used in ditfusion transfer processes for preparing positive silver images. After the imbibition period, the image-receiving element was separated from the photosensitive element and was found to contain a positive image.

It is also contemplated that the novel solvent system of this invention may be employed in photographic processes for preparing silver transfer images without fixation of the negative image.

As was mentioned previously, the present invention is particularly useful in combination with the invention described and claimed in the aforementioned copending application Ser. No. 438,044. However, it is to be expressly understood that the solvent-fixer agents of the present invention may be employed in processing compositions containing any of the developing agents known in the art. i

It will be appreciated that the novel processing compositions of this invention may also contain the various ingredients heretofore incorporated in the processing compositions for specific processes, e.g., preservatives, antifoggants, toning agents, film materials, etc.

Since certain changes may be made in the above products and processes Without departing from the scope of the invention herein involved, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. A photographic processing composition for developing and fixing an exposed light-sensitive silver halide emulsion containing a developable image to provide a negative image which comprises an aqueous composition containing a silver halide developing agent and a silver halide fixer, said fixer comprising a mixture of cysteine and a nitrogenous base, said mixture being in an amount sufiicient upon development of said emulsion to fix said negative image.

2. A photographic processing composition as defined in claim 1 including a relatively small amount of a compound selected from the group consisting of sodium thiosulfate and potassium thiosulfate, said amount being suflicient to lower appreciably the time necessary to obtain said fixed negative image, said amount being insufficient by itself to provide said fixed negative image.

3. A photographic processing composition as defined in claim 1 wherein said nitrogenous base is a volatile compound.

4. A photographic composition as defined in claim 1 wherein said nitrogenous base is a compound selected from the group consisting of ammonia, sec. amylamine, ethylamine, n-butylamine, allylamine, diethylamine, dipropylamine, trimethylamine, triethanol amine, diethylene triamine, triethylene tetramine, N-hydroxyethyl propylene diamine, trimethylene diamine, ethylene diamine, aminoethyl ethanol amine, hydroxyethyl diethylene triamine, tetraethylene pentamine, guanidine hydrochloride, piperidine, pyrrolidine, 2,5-dimethyl piperazine, polyethylene imine, symmetrical dimethyl hydrazine and unsymmetrical dimethyl hydrazine.

5. A photographic processing composition which comprises an aqueous composition containing a silver halide developing agent and a silver halide fixer, said fixer comprising a mixture of cysteine and diethylamine.

6. A photographic processing composition as defined in claim 4 including a relatively small amount of a compound selected from the group consisting of sodium thiosulfate and potassium thiosulfate, said amount being suflicient to lower appreciably the imibibition time necessary to obtain said fixed negative image, said amount being insufiicient by itself to provide said fixed negative image.

7. In a photographic processing composition for developing and fixing an exposed silver halide emulsion, said composition comprising an aqueous alkaline solution containing a silver halide fixing agent, a high-energy aminophenol silver halide developing agent and a lowenergy silver halide developing agent selected from the group consisting of the ascorbic acids and hydroxylamines, said low-energy developing agent being present in substantially greater concentration than said high-energy developing agent, the amount of each of said low-energy and high-energy silver halide developing agents alone 'being insufficient to develop appreciable negative density, but said respective amounts together providing a synergistic effect whereby said combined developing agents are capable of providing, upon development, a negative image having a desired usable density; the improvement which comprises employing as said fixing agent a mixture of cysteine and a nitrogenous base in an amount sufiicient to fix the negative image formed upon development of said exposed silver halide emulsion.

8. A photographic composition as defined in claim 7 wherein said nitrogenous base is a compound selected from the group consisting of ammonia, sec. amylamine, ethylamine, n-butylamine, allylamine, diethylamine, dipropylamine, trimethylamine, triethanol amine, diethylene triamine, triethylene tetramine, N-hydroxyethyl propylene diamine, trimethylene diamine, ethylene diamine, aminoethyl ethanol amine, hydroxyethyl diethylene triamine, tetraethylene pentamine, guanidine hydrochloride, piperidine, pyrrolidine, 2,5-dimethyl piperazine, polyethylene imine, symmetrical dimethyl hydrazine and unsymmetrical dimethyl hydrazine.

9. A photographic composition as defined in claim 7 wherein said nitrogenous base is a volatile compound.

10. In a photographic processing composition for developing and fixing an exposed silver halide emulsion, said composition comprising an aqueous alkaline solution containing a silver halide fixing agent, a low energy silver halide developing agent selected from the group consisting of ascorbic acids and hydroxylamines and'a high energy silver halide developing agent selected from the group consisting of para-aminophenols containing, in a position ortho to the phenolic hydroxyl group, at least one substituent selected from the group consisting of amino, lower alkyl and lower alkoxy groups; the improvement which comprises employing as said fixing agent a mixture of cysteine and diethylamine.

11. A photographic process for developing and fixing an exposed silver halide emulsion to form a negative image thereon, Which comprises contacting said exposed emulsion with an aqueous processing composition containing a silver halide developing agent and a mixture of cysteine and a nitrogenous base, reducing exposed silver halide to image silver and forming a transparent, silver complex from unexposed silver halide with said mixture.

12. A photographic process as defined in claim 11 wherein said nitrogenous base is a compound selected from the group consisting of ammonia, sec. amylamine, ethylamine, n-butylamine, allylamine, diethylamine, di propylamine, trimethylamine, triethanol amine, diethylene triamine, triethylene tetrarnine, N-hydroxyethyl propylene diamine, trimethylene diamine, ethylene diamine, aminoethyl ethanol amine, hydroxyethyl diethylene triamine, tetraethyl pentamine, guanidine hydrochloride, piperidine, pyrrolidine, 2,5-dimethyl piperazine, polyethylene imine, symmetrical dimethyl hydrazine and unsymmetrical di methyl hydrazine.

13. A photographic process as defined in claim 11 wherein said nitrogenous base is a volatile compound.

14. A photographic process as defined in claim 11 wherein said processing composition includes a relatively small amount of a compound selected from the group consisting of sodium thiosulfate, said amount being sufiicient to lower appreciably the imbibition time necessary to obtain a fixed negative image, said amount being insufiicient by itself to provide said fixed negative image and potassium thiosulfate.

15. A photographic process as defined in claim 11 in cluding the steps of transferring an imagewise distribution of said silver complex, at least in part, to a superposed image-receiving stratum to form a silver transfer image.

16. A photographic process for developing and fixing an exposed silver halide emulsion to form a negative image thereon, which comprises contacting said exposed emulsion with an aqueous processing composition containing a silver halide developing agent and a mixture of cysteine and diethylamine, reducing exposed silver halide to image silver and forming a transparent, soluble silver complex from unexposed silver halide with said mixture.

17. In a process for developing and fixing an exposed silver halide emulsion to form a negative image thereon comprising the step of contacting said emulsion with a processing composition comprising an aqueous alkaline solution containing a silver halidefixing agent, a highenergy aminophenol silver halide developing agent and a low-energy silver halide developing agent selected from the group consisting of the ascorbic acids and hydroxylamines, said low-energy developing agent being present in substantially greater concentration than said high energy developing agent, the amount of each of said low-energy and said high-energy silver halide developing agents alone being insufiicient to develop appreciable negative density, but said respective amounts together providing a synergistic effect whereby said combined developing agents are capable of providing, upon development, a negative image having a desired usable density; the improvement which comprises employing as said fixing agent a mixture of cysteine and a nitrogenous base in an amount suflicient to fix the negative image formed upon development of said exposed silver halide emulsion; and forming a transparent silver complex from unexposed silver halide with said mixture.

18. A photographic process as defined in claim 17 wherein said nitrogenous base is a compound selected from the group consisting of ammonia, sec. amylamine, ethylamine, n-butylamine, allylamine, diethylarnine, dipropylamine, trimethylamine, triethanol amine, diethylene triamine, triethylene tetramine, N-hydroxyethyl propylene diamine, trimethylene diamine, ethylene diamine, aminoethyl ethanol amine, hydroxyethyl diethylene triamine, tetraethylene pentamine, guanidine hydrochloride, piperidine, pyrrolidine, 2,5-dimethyl piperazine, polyethylene imine, symmetrical dimethyl hydrazine and unsymmetrical dimethyl hydrazine.

19. In a process for developing and fixing an exposed silver halide emulsion, which comprises contacting said emulsion with a processing composition comprising an aqueous alkaline solution containing a silver halide fixing agent, a low energy silver halide developing agent selected from the group consisting of ascorbic acids and hydroxylamines and a high energy silver halide developing agent selected from the group consisting of para-aminophenols containing in a position ortho to the phenolic hydroxyl group at least one substituent selected from the group consisting of amino, lower alkyl and alkoxy groups, reduc ing the exposed silver halide to image silver and forming a soluble silver complex from unexposed silver halide with said fixing agent, the improvement which comprises employing as said fixing agent a mixture of cysteine and diethylamine, and forming a transparent, stable silver complex from unexposed silver halide with said mixture.

References Cited UNITED STATES PATENTS 2,857,274 10/1958 Land et a1. 96-66 X 2,984,565 5/1961 Morse 96-29 OTHER REFERENCES Abstract of: Nishimura et al., Study of Retarders in Emulsions, Sci. et Ind. Phot., 22, 46-7 (1951), Chemical Abstract 45: $268k.

Abstract of: Valladas-Dubois, S.: Complexes of Cysteine With Silver Ion. Compt. Rend, 231, 53-5 (1950), Chemical Abstract 44:98530.

Fieser, L. F., et al., Organic Chemistry. Reinhold Publishing Corporation, New York, 1956, p. 421.

Haist, G. M., et al., Organic Silver-Complexing Agents for Photographic Monobaths, Phot. Sci. and Eng, 5, 4, July-August 1961, pp. 198203.

NORMAN G. T ORCHIN, Primary Examiner,

C. E. DAVIS, Assistant Examiner,

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,343,958 September 26, 1967 Meroe M. Morse It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 42, "makes" should read make Column 7, line 41, after "sodium thiosulfate" insert and potassium thiosulfate lines 44 and 45, cancel "and potassium thiosulfate".

Signed and sealed this 30th day of September 1969.

(SEAL) Attest:

WILLIAM E. SCHUYLER, JR.

Commissioner of Patents Edward M. Fletcher, Jr.

Attesting Officer 

11. A PHOTOGRAPHIC PROCESS FOR DEVELOPING AND FIXING AN EXPOSED SILVER HALIDE EMULSION TO FORM A NEGATIVE IMAGE THEREON, WHICH COMPRISES CONTACTING SAID EXPOSED EMULSION WITH AN AQUEOUS PROCESSING COMPOSITION CONTAINING A SILVER HALIDE DEVELOPING AGENT AND A MIXTURE OF CYSTEINE AND A NITROGENOUS BASE, REDUCING EXPOSED SILVER HALIDE TO IMAGE SILVER AND FORMING A TRANSPARENT, SILVER COMPLEX FROM UNEXPOSED SILVER HALIDE WITH SAID MIXTURE.
 15. A PHOTOGRAPHIC PROCESS AS DEFINED IN CLAIM 11 INCLUDING THE STEPS OF TRANSFERRING AN IMAGEWISE DISTRIBUTION OF SAID SILVER COMPLEX, AT LEAST IN PART, TO A SUPERPOSED IMAGE-RECEIVING STRATUM TO FORM A SILVER TRANSFER IMAGE. 